A wavelength-selective photonic-crystal waveguide coupled to a nanowire light source

The efficient delivery of photons from light sources to photonic circuits is central to any fibre-optic or integrated optical system. Coupling light emitters to optical fibres or waveguides determines the photon flux available in, and therefore the performance of, photonic devices used in applications such as optical communication and information processing. Many solutions have been proposed to improve impedance matching in light-emitting diode-to-fibre or photonic-crystal cavity-to-waveguide systems; however, the efficient coupling of integrated light sources into nanophotonic circuits remains a challenge. Here, we propose an optically or electrically driven photonic structure that uses active semiconductor nanowires to light up photonic-crystal waveguides. The photonic crystal is used to either guide or filter out different colours of light as desired. In addition, we report an active nanowire-based optical structure that can generate two different colours of light and then send them in opposite directions. The hybrid nanowire/photonic-crystal waveguide represents a significant advance towards all-optical processing in nanoscale integrated photonic circuits and a new addition to the nanophotonic toolbox.